New member here that could use some help.

I have a new project, a 1988 heritage.
Has some discolouring on the back fender(think the old owner left a rag with some strong chems on it..)
and a few rust bubbles that I need to fix.
So I could use some help finding the right colours for it.

What's the best way to fix the rust?
Sand paper and paint the the parts that need painting?
The discolouring might go away with some polishing...

Best Regards from Sweden